Whisk olive oil, lime juice, garlic, chili powder, cumin, paprika, salt, and pepper in a medium bowl.
Add chicken and turn to coat well. Marinate 15–30 minutes while you make the salsa.
Preheat grill to medium-high heat and oil the grates lightly.
Combine peaches, red onion, jalapeño, cilantro, lime juice, honey, olive oil, and 1/4 tsp salt in a bowl. Toss gently.
Grill chicken 5–7 minutes per side, or until an instant-read thermometer reads 165°F.
Rest chicken 5 minutes on a cutting board to keep juices in.
Slice chicken and top generously with peach salsa. Serve right away.